1. Field of the Invention
The present invention relates to a method for the addressing of elementary heads of a multitrack head used for recording on a magnetic medium, a magnetic head implementing this method and an addressing circuit for such a head.
2. Description of the Prior Art
There is a known multitrack magnetic head, with a matrix arrangement of elementary heads, as disclosed for example in the document EP-A-0 340 085. A head such as this works in a substantially linear mode, i.e. the field that each elementary head creates at its gap is practically proportional to the sum of the excitation currents of this head (line and/or column current). The point of operation of each elementary head is chosen in such a way that the coercive field h.sub.c of the magnetic tape on which the head records information is located between the fields h/3 and h created by the head for excitation currents of respective values I/3 and I, the current I being the maximum excitation current.
The column signal is either a bipolar pulse with an amplitude of 2I/3 selecting the entire column of corresponding elementary heads or a signal of zero amplitude such that this column is not selected. The line writing signal is necessarily a pulse with a width greater than that of the bipolar pulse, and has an amplitude of +I/3 (to write +1) or -I/3 (to write -1).
In a known head such as this, the signal used to select one column alone may record an undefined intermediate state on the magnetic medium. The line signals sent to all the cells of the selected column make it possible to define the magnetic state to be recorded but thus dictate a writing operation by all these cells.